The present invention relates to an apparatus and a method for detecting the accuracy of drilled holes on a printed circuit board (PCB) and, more particularly, to an apparatus and a method, which can quickly and accurately detect the accuracy of drilled holes on a PCB.
In prior art, there are two types of apparatuses for detecting drilled holes on a PCB. For the first type of apparatus, a PCB is placed on an optically-scanned conveying belt. Through the movement of the conveying belt, various data of the drilled holes on the PCB can be scanned out via an optical scanning tool and transferred to a processing unit to check whether they conform to stored data. However, because an accurate positioning procedure is absent from this type of apparatus, only the counts and sizes of drilled holes can be detected. The errors of positions of drilled holes and the burrs and distortions arising from drilling process can not be detected. For the second type of apparatus, detection is performed through the help of position data of drilled holes stored in a computer aided design (CAD) tool or a drilling/processing program. A charge-coupled device (CCD) camera is gradually moved to detect one hole by one hole. Although the positions, sizes, and counts of drilled holes can be detected, the speed is limited by the counts of drilled holes and the distances between them. Moreover, because time is required for moving to and then positioning each drilled hole, the detection speed will be very slow.
Furthermore, due to increased demand in use, the required accuracy of a PCB becomes higher and higher, and the counts of drilled holes thereon become more and more. The above way of using an optically-scanned conveying belt can not satisfy the required accuracy of drilled holes. Once a drilled hole has a slight error, the PCB may be useless. On the other hand, the above way of using position data of drilled holes stored in a CAD tool to position an optical scanning tool is also inapplicable. When there are a lot of drilled holes, it will take much time, resulting in much lower throughput than that of a drilling machine.
The present invention aims to provide an apparatus and a method for detecting the accuracy of drilled holes on a PCB to resolve the above problems.
The primary object of the present invention is to provide an apparatus and a method for detecting the accuracy of drilled holes on a PCB so that quick scanning of drilled holes on a PCB can be achieved.
The second object of the present invention is to provide an apparatus and a method for detecting the accuracy of drilled holes on a PCB so that the positions of drilled holes can be accurately detected.
Another object of the present invention is to provide an apparatus and a method for detecting the accuracy of drilled holes on a PCB so that the sizes of drilled holes can be accurately detected.
Yet another object of the present invention is to provide an apparatus and a method for detecting the accuracy of drilled holes on a PCB so that the counts of drilled holes can be accurately detected.
Still yet another object of the present invention is to provide an apparatus and a method for detecting the accuracy of drilled holes on a PCB so that the wall roughness of drilled holes can be accurately detected.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which: